(1) Field of the Invention
This invention relates to improvements in oil-in-water anionic bituminous emulsions. More particularly, this invention relates to the production of oil-in-water anionic bituminous emulsions with the aid of a particular anionic emulsifying agent comprising an alkali metal salt of an alkali lignin and an ethylene oxide adduct of an alkyl phenol.
(2) The Prior Art
Aggregates for road building are generally coated with suitable asphalt mixes which include bitumens which affect the coating of the aggregates. The aggregates used are, of course, sand, gravel and other suitable and well known aggregates.
To prevent the emulsion from leaving the aggregate, known as "stripping", the asphalt mixes are provided with additives which are usually of either cationic or anionic surfactants. Formulators are continuously attempting to use more effective surfactants of both the cationic and anionic varieties. Although satisfactory results can be obtained with certain types of both surfactants, certain deficiencies, both as to performance and price, leave room for considerable advancement in this field.
The use of lignin-type materials, specifically lignin amines for use in anionic bituminous emulsions, are disclosed in U.S. Pat. No. 3,123,569 to M. J. Borgfeldt. Further, it is also known to use ethers formed from ethylene oxide and nonyl phenol as surfactants in bituminous emulsions as disclosed in U.S. Pat. No. 3,366,500 to Kracauer. However, no one has shown the advantages obtained by the use of an ethylene oxide adduct of nonyl phenol together with the particular lignin materials of this invention in anionic bituminous emulsions.
Accordingly, it is a general object of the present invention to provide an anionic emulsion for coating aggregates for road building and the like.
Another object of the present invention is to provide an anionic bituminous emulsion for coating aggregates for road building and the like which has universal action, that is, it can be used for all different types of asphalt mixes for the coating of all different types of aggregate.
Other objects, features and advantages of the present invention will be apparent from the foregoing detailed description of the invention.